1. Field of the Disclosure
The present disclosure relates to a control unit for a circuit breaker and a controlling method thereof, and particularly, to a control unit for a circuit breaker, capable of controlling and monitoring various types of switches such as a circuit breaker and a switchgear included in power system equipment, by being formed as a module detachable to the switches, or by being formed as an independent module spaced from the switches, and a controlling method thereof.
2. Background of the Disclosure
Generally, as shown in FIG. 1, a power system is composed of a circuit breaker to be controlled, and an Intelligent Electronic Device (IED) or a relay (hereinafter, will be referred to as a ‘relay’) for controlling the circuit breaker. The circuit breaker and the relay are installed as a pair.
As shown in FIG. 2, a power device configured to supply a current to a magnetization coil for operating the circuit breaker, and a contact signal line configured to connect the relay to the circuit breaker, are connected between the relay and the circuit breaker.
A length of the contact signal line may be within the range of several meters (m)˜several hundred meters. In a case where two relays are installed at two circuit breakers, the circuit breakers are connected to the relays by two contact signal lines. In this case, the two contact signal lines are individually formed.
In a case where the relay and the circuit breaker are installed at different buildings, the contact signal line should be buried between the buildings. In this case, the contact signal line may be grounded due to lightning and its inferior coating. This may cause a difficulty in controlling the circuit breaker with reliability.
Further, one relay can control one or two circuit breakers due to its limited capacity of a contract for control command. If a single line using a DC voltage is installed with a long length, it is difficult to obtain reliability of a signal due to a stray voltage, etc.